@CaelaNotKayla
I think if the agent questions, or when you go through a scanner at the airport presenting as female and the inspector who is scanning notices something that is male looking, you can say you are MTF transitioning. But it is simpler to dress a bit ambiguously if your travel documents still list you as male.
PreCheck lines are also shorter that may be of help. With TSA changing their practices next month that may also be easier starting next month, as you stated.
Chrissy